The Iranian president's fresh rebuke of political foes, along with continued defiance on the nuclear issue, suggest that recent post-election unrest hasn't prompted him to change his ways.

BEIRUT — Three months after Iranian President Mahmoud Ahmadinejad derided his opponents as "dirt and dust," sending hundreds of thousands of angry protesters into the streets, he risked enraging them again Monday by likening them to "pollutants" staining "the gown of the revolution."

The comment, during prepared remarks at a news conference, drew an immediate rebuke from a conservative clerical association in the holy city of Qom, which urged the president and his staff to "concentrate their minds seriously on economic woes and social challenges and avoid uttering unnecessary and provocative remarks."

But along with Ahmadinejad's defiant and boastful tone on the sensitive nuclear issue, Monday's statement also suggested that three months of the worst domestic unrest in the Islamic Republic's history had not caused the president to change his ways.

At the news conference, the president dismissed the Obama administration's mid-September deadline for responding to Western offers of talks about Iran's nuclear program and said threats of sanctions or war would not move Tehran.

"The present approach will bring [the West] nothing," he told reporters. "Iranians have learned their lessons well on how to live through crises and go unscathed. All crises will be turned into opportunities. The Iranian nation will never be harmed under any circumstances."

As the U.N. General Assembly prepares to convene this month, Ahmadinejad's tone on domestic and international affairs suggests no solution on the horizon for an issue that has divided the Security Council and shaken the region.

In Vienna on Monday, International Atomic Energy Agency chief Mohamed ElBaradei lamented a "stalemate" in efforts to begin talks over Iran's nuclear program. He also took Tehran to task for refusing to answer questions about possible military aspects of its program and abide by Security Council demands to stop sensitive nuclear activities.

"Iran's future intentions concerning its nuclear program need to be clarified to respond to the international community," he told the atomic agency, according to a copy of his prepared remarks.

Iran insists its nuclear enrichment program is meant solely for peaceful energy production and scientific advancement. Ahmadinejad maintained that Iran had resolved all questions regarding the nature of its nuclear program.

But the U.S., Israel and international arms control experts strongly disagree. They suspect that Iran is slowly creating the capacity to produce nuclear weapons, and point to a set of documents, derided as forgeries by Tehran, that purport to show that Iran engaged in experiments consistent with a clandestine nuclear weapons program until 2003.

ElBaradei urged Iran to "respond fully to all the questions raised by the agency" about the documents.

The Obama administration has called for direct diplomatic talks with Iran as a way of resolving the nuclear issue, and asked that Tehran respond to its offer before the General Assembly convenes.

Ahmadinejad said he planned to attend the General Assembly gathering to meet with the American people and media, but would "debate" U.S. officials only in public.

"The era of secret and clandestine meetings to solve problems has ended," he said. "In the presence of world media, anything can be discussed."

Later, authorities stormed an office where supporters of opposition leader Mir-Hossein Mousavi are investigating claims of abuse by security forces. Those conducting the raid seized documents while refusing to show a warrant or identification, according to the website Norooznews.ir.